Been working on this exact question for a while. No to train. No to driving back at midnight! Couldn’t find that Irish Train some talked about. We decided to do the package offered through Clemson. Hotel, transportation and a few other Clemson related things. Yes, it costs a bit, but there are really no other options.
Chicago’s great, but I found RT tickets from Atlanta to Grand Rapids, MI for less than $200. Easy car rental and drive (2 hours to South Bend). Found a 4* hotel about 1/2 hour from campus for a normal rate.